


Close Quarters "Combat"

by Grimalkenkid



Category: Fate/Grand Order, Fate/stay night & Related Fandoms
Genre: Competition, Consensual Sex, F/M, M/M, Oral Sex, Plot What Plot/Porn Without Plot, Threesome - F/M/M
Language: English
Status: Completed
Published: 2018-02-20
Updated: 2018-02-20
Packaged: 2019-03-21 19:25:55
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,066
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13747668
Author URL: https://archiveofourown.org/users/Grimalkenkid/pseuds/Grimalkenkid
Summary: Competition isn't always the best way to relax, but Ritsuka finds she likes it when it's like this.





	Close Quarters "Combat"

The past few missions had been exhausting but worth it. Through the combined efforts of everyone at Chaldea, another singularity was no more. In the command room, Roman and Mash celebrated with the other mages and more than a few Servants. Each and every one of them deserved it.

Ritsuka, on the other hand, returned to her room almost immediately. All she needed was a cup of tea, a bite to eat, and a week long nap. The sandwich disappeared as quickly as she made it, and the tea was left to steep, so the young Master began disrobing.

A sharp rap on the door made her pause halfway through unbuttoning her shirt. _Who is it this time?_ Ritsuka sighed to herself, making certain she was decent before answering. “Come in! The door’s open.”

She fully expected Alexander or Elisabeth to come barreling in, ready to drag her back to the festivities she was surely missing. Ritsuka had a small lecture on the importance of rest ready to go when she saw the blue-haired caster slink into the room.

“Oh, hello, Cu.” The young Master relaxed a little. He probably wouldn’t try bringing her back to the party. “What can I do for you?”

Cu Chulainn put a hand on his hip in a relaxed sort of way and raised an eyebrow. “What you could do for me? I don’t think so. After the stunts you pulled, I just wanted to, uh, see how you were doing.”

“I’m doing okay,” she replied quickly. Her eyes drifted to the teacup. It was probably done steeping by now. “I just need a bit of rest and relaxation. I’ll be putting you back to work in no time flat.”

He rolled his eyes. Chulainn always had a look of frustrated ease, like that of someone who was good at their job but didn’t particularly like it. It hadn’t helped matters when Ritsuka summoned him again. Well, summoned another aspect of him. And they couldn’t agree on anything. She almost welcomed Arthur and Gilgamesh’s spats to the stuff the Chulainn’s butted heads about.

Right now, though, Chulainn hardly looked annoyed. The young master could never tell what he was thinking, but within a few seconds, something had him smiling like a hyena. “Ah, is that it?” he sighed, striding lazily around the room. Ritsuka watched him step softly across the cold, metal floor, leaning his staff against the wall before sitting purposefully on the side of her bed. Then he gently patted the spot next to him.

In the back of her mind, Ritsuka had an idea on what he was thinking. That tidbit of information was having trouble making it to the front of her tired mind, though. She plopped down in the spot Chulainn indicated without much thought, glancing at the caster from the corner of her eye.

“If it’s relaxation you want,” he whispered in her ear, “then I know just what we can do.” Every honeyed word was heavy with desire. Ritsuka turned her head to meet his gaze and swallowed as she realized just how close he was. Chulainn had the same cocksure grin he always did, but she could also see just the slightest bit of affection twinkling in his eyes. She almost didn’t notice how he brought his arm around her shoulder and began thumbing the collar of her shirt.

Ritsuka had no idea what to say. Of course she had fantasized about some of her Servants and wondered what it would be like to lay with a literal embodiment of heroism. But their entire situation – mage and heroic spirit, the end of the world – made that fantasy seem utterly impossible and more than a little odd. It didn’t help that she could never work up the courage to even ask.

But Chulainn was there. He was willing. And, if she was reading the intensity in his gaze correctly, he was eager.

“So?” he asked. His smile wavered almost imperceptibly.

That one syllable snapped her back to the present and the offer he had made. Ritsuka hadn’t thought anything would stop the caster when he put his mind to something, but he was definitely waiting for permission.

_Well, may as well. Carpe diem, and such._

Ritsuka leaned forward and pressed her lips to his. That was, apparently, all Chulainn needed. He set to undoing the buttons of her shirt even as he took control of their kiss, pulling her halfway onto his lap. He was exactly the kind of forceful lover she thought he’d be, and all she could think to do was throw her arms around his chest and sigh as his hand traveled up her thigh.

She had no idea where to focus. Despite being a caster, Chulainn had defined muscles from a lifetime of wielding a lance. His clothing left little to the imagination, but that hadn’t prepared her for just how hard and unyielding his body was. He left her little time to process this, as he pulled away from her lips just long enough to start kissing down her neck. Ritsuka gasped when she felt his fingertips lightly stroke her through her tights. She reflexively clamped her legs together. It had been quite a while since anyone else touched her there.

Chulainn chuckled. “Mm? Not yet, then?” he smirked against her skin. “Please relax, Master. I’ve yet to meet a woman who leaves my bed unsatisfied.”

“She might if you keep going like that.”

Chulainn froze immediately. It took Ritsuka a little longer to realize that someone else had spoken. In her room.

She looked towards the source of the voice. A familiar, green-clad archer was leaning against the doorframe. The young master wondered why she hadn’t heard the door open, but that seemed like a very small issue comparatively. It was one thing to have a Servant come in uninvited; it was quite another for said Servant to come in while Chulainn had his hand up her skirt.

“Do you mind?” the caster growled, glaring at Robin. He continued lightly stroking between her legs, as if daring the archer to interrupt them.

Robin must have noticed, because he pouted and started towards them, offhandedly closing the door behind him. “Actually, I do. Who said you could monopolize our master’s time like this?”

Ritsuka buried her face in the fluff of Chulainn’s hood. She hadn’t thought her face could get any redder than it had when Kiyohime professed her undying, obsessive love for the young master in front of the entire Chaldea staff. _Evidently, that was not the most embarrassing thing that could happen here_ , she thought. _My imagination sure is lacking._

“She did,” Chulainn answered the archer’s question, smirking since there was nothing Robin could do about it. “Now run along, little bird. Don’t you have some _other_ doves to seduce?”

“Master,” Robin pleaded, “you can’t be serious. Just… look… He’s holding you like a sack of potatoes. I’ve seen better finesse from a hungry bear.”

The tone in his voice made the archer sound like a kicked puppy, and Ritsuka forced herself to lift her head and look him in the eye. Robin was far easier to read. So much so that she could almost predict the exact words he used next.

“If it were me, then I’d definitely treat you right.”

Ritsuka could feel Chulainn taking in a breath to berate the archer or something like that. She did _not_ want to be in the middle of a Servant spat, and so she said the first words that came to mind in her worked-up state. “If you’re so keen on one-upping each other, why not just join in? It would save time.”

No one spoke for a good minute. Both Servants looked dumbfounded, like they hadn’t realized that was an option. They exchanged glances, and some kind of understanding passed between them, though Ritsuka didn’t notice. As the silence stretched out, her cheeks went a darker shade of crimson, and she slapped her hands over her face.

“N-nevermind,” she practically whispered. “I don’t know why I said that.”

“Well,” Chulainn sighed as he relaxed his hold on her, “if you want that much attention, I’d be, um, happy to oblige. I’m the best lover you’ll ever have, but I suppose it helps to have something for comparison.”

“Funny, I was about to say the same thing,” Robin said a little bitterly, but not as upset as he had been a moment before.

When Ritsuka didn’t respond, the Servants said, almost in unison, “Master?”

If someone had told her that morning that she’d be the focal point of a threeway before dinner, she would’ve first slapped them and then told them to go home because they were obviously too drunk to function. This entire situation had seemed implausible at best until Chulainn had walked through her door, and now that the option was there, she wasn’t entirely sure what to do. She settled on just being honest.

“Sure. Why not?” Ritsuka put her hands in her lap and smiled awkwardly between the two handsome men in the room with her. “I have no idea what I’m doing.”

The tension in the room melted away. Whether it was because of her admission or because they were all on the same page now didn’t really matter. Now Ritsuka felt like she could truly relax, and she could feel herself getting wet again at the prospect of what was going to happen.

Chulainn’s hand found its way back up her skirt, and he grinned. “All you need to do is say if you like something or not.” Once again, he claimed her lips and partially turned her towards him.

Robin eagerly settled on Ritsuka’s other side, his cloak and boots cast aside unceremoniously. She tensed slightly as his weight caused the bed to shift, but the archer held a hand to her back to make sure she didn’t shift with it. Immediately after, he pressed his chest against her back, and Ritsuka was vaguely aware of how he was now sitting cross-legged on her bed. Chulainn and his adventurous tongue _were_ occupying a lot of her attention. Robin took her lack of reaction as a challenge and grasped her hand, lifting it to his lips and laying a tender kiss on her wrist. Slowly - almost too slowly - he moved up her arm, to her shoulder, to the back of her neck. Where Chulainn’s kisses had been playful and sharp, Robin took his time, leaving soft kisses across her body. He mumbled something about how soft her skin was or some such fluff, but Ritsuka was far more pleased with how he laced his rough-skinned fingers through hers.

When Chulainn pulled away to get a breath in, she sighed, “Robin…” She felt the green archer smile.

In the same moment, the other man pouted and began pulling down on her tights. The part of Ritsuka’s mind that wasn’t consumed with desire realized that they were counting points. And Robin was already in the lead.

Chulainn wouldn’t let that stand. He slid off the bed and knelt in front of the young master, tossing her leggings and underwear to the side. Robin took the opportunity to wrap his other arm around her and caress her breast, but she found herself focusing on the mischievous light twinkling in the caster’s eyes.

“That was such a quiet moan, Master,” Chulainn chuckled, his eyes flicking between her and Robin. “Let me hear you scream.” With that, he hooked Ritsuka’s legs over his shoulders and nestled his face between her thighs.

She squeaked the moment she felt his tongue along her folds. It was direct and to the point; Chulainn wasn’t going to waste any time teasing and tantalizing her. Unlike her previous tumbles, however, this wasn’t because he lacked skill or finesse. The caster knew exactly what he was doing, and he would do it. His tongue flicked in and out, each stroke tightening the coils in her stomach. Chulainn kept his hands moving, stroking along the inside of her thighs with warmth that shouldn’t have been possible.

 _Magic,_ Ritsuka thought, suddenly aware of how chilly the room was. She gasped as a shiver ran through her body, unsure whether it was due to the cold or the things Chulainn was doing with his mouth. Her toes curled, and she tried to pull the caster closer to her core.

She felt him chuckle more than she heard it. He obeyed her command as well as if she’d said it aloud and picked up his pace. Ritsuka moaned loudly and closed her eyes, tilting her head back as Chulainn rushed her to the edge of ecstasy. She rocked gently against his mouth until the warm tension finally snapped.

“Ah, Cu… Cu!” the young master gasped between waves of pleasure. Her free hand sought something to grasp, coming to rest on Robin’s leg as she rode out the rest of her orgasm. Chulainn kept stroking and teasing her through the pleasure, only pulling away when her body relaxed.

“Hm… not quite as loud as I wanted,” the caster smirked, wiping her juices from his chin. “Guess we’ll have to try harder then.” He lightly traced a finger around her entrance, the only heads-up he gave before easing it inside her.

Ritsuka whimpered at the sensation. Whatever magic he had called upon, he was still using, as the pleasant warmth traveled along his hand and into her core. So soon after a climax, she felt the tension build far faster.

“Master,” Robin whispered in her ear. “I can’t do much like this. Please let me show you what I can do.”

Ritsuka felt a bit ashamed. She had nearly forgotten the archer was there, but he was so slow and solid that everything Chulainn did overshadowed it by magnitudes. If it had just been her and Robin, she thought she wouldn’t have been able to think about anything but his gentle attention to every inch of her body. Ritsuka turned her head to face him.

Robin met her gaze intently, waiting for an answer or something allowing him to act. She still had no idea what to do, but this close…

Ritsuka closed the centimeters between them and pressed her lips to his. This was something he knew, as Robin responded immediately, exploring her mouth like a wary hunter. At the same time, she trailed her hand up his thigh, cupping his arousal through his pants the moment she felt it.

The green archer broke their kiss to sharply inhale. There was a bit of confusion in his mossy green eyes, but Ritsuka continued as if nothing had changed. He made small sounds from the back of his throat as she stroked over his growing hardness. The pleasant tingles she felt between her legs faded into the background at the knowledge that she was making a proud Servant whimper in pleasure.

A sharp nip at the soft skin of her leg reminded her that Robin wasn’t the only Servant in the room, however.

“Ow,” she said, though it hadn’t really hurt that much. Turning from the kiss, she looked at Chulainn, who looked back with a thoroughly put-out expression.

“Oi,” the Caster said, “I’m still down here. And I haven’t heard you scream yet.”

Ritsuka remembered what had initially prompted this ménage à trois and sighed. She had no idea what the criteria were, but both men were still competing, at least in a certain sense. For her part, the young master just wanted to have fun. And that didn’t seem like a feasible outcome if one of their number was still unsatisfied.

At least, that’s how Ritsuka saw it.

Pulling her hands away from Robin, she patted the bed in front of her. “Cu, please get on the bed.” Then, she added, “And lie back.”

Chulainn raised an eyebrow but reluctantly withdrew his hand, licking her juices from his fingers without breaking eye contact. He eased back onto the bed and leaned back against the headboard. Almost self-consciously, he crossed his arms, waiting for her next instruction.

Ritsuka turned to Robin and smiled. “Now you’ll have a chance to show me what you’re capable of, okay?”

When the archer nodded, she got up on her knees and placed herself between Chulainn’s legs. The caster’s eyes widened in realization, and he lowered his hands to his sides. Ritsuka slid his robes down over his hips and gave him a smug smirk as she saw that he was nearly rock hard already. Making sure that she was positioned comfortably, she once again looked over her shoulder and motioned for Robin to join.

“Whenever you’re ready,” she cooed as the archer knelt behind her. “I think Cu did enough prep work.” Ritsuka was surprised at how easily the words came. It was like in combat, where the ebb and flow of battle made the next action clear. Part of her wondered if the two men were falling into the same rhythm.

The other part really wanted to get to the fun bits. As she heard the clink of a belt buckle coming undone from Robin, Ritsuka reached out and lightly ran her fingers up Chulainn’s length.

“Master, are you—” said a voice that wasn’t hers.

Or Chulainn’s.

Or Robin’s.

Ritsuka took a deep breath and let it out slowly. “Yes?” she asked, turning towards the voice, the owner of which had just opened the door.

Diarmuid looked back at her with a completely blank expression. “I… I’ll come back later.”

As quickly as he had come, the Irish lancer slid the door shut. The trio on the bed waited until his soft footsteps had faded into silence before they dared to speak again.

“Oh, good,” Chulainn snarked. “I was worried we would have to add another one to this pile.”

“I’ll lock the door,” Ritsuka sighed. She had just gotten comfortable, but her poor circulatory system couldn’t handle having to blush this many times in the span of an hour. She rushed to the door and turned the deadbolt, hurrying back as quickly as she could without tripping. “Okay… where were we? Ah, right. Robin, whenever you’re ready.”

She hadn’t been sure how willing they would be to continue after being interrupted like that, but her authoritative tone seemed to set them at ease. On the battlefield, it was the tone she used whenever she had a backup plan. It was a voice they had come to associate with reassurance and calm. Robin leaned down to place a kiss between her shoulders before he gripped her hips to guide his length to her entrance. Ritsuka sighed in anticipation but turned her attention to Chulainn.

He was good at hiding it, but the caster was aching for her touch by then. His eyes, normally a bright red, were dark with interest, and his skin was beginning to shine with beads of sweat. Ritsuka wasn’t surprised in the slightest at the guttural moan he made when she stroked him from base to tip. Excitement swelled in her chest at the thought of drawing even more lewd sounds from him.

She was the one who gasped, though, as Robin slid inside her. There was no stretching or pain, just a slight fullness that made her want motion as well. The archer wrapped his arms around her and gently rubbed her clit. “Is this okay?” he asked tentatively.

“Mm hm,” Ritsuka nodded. Her head was buzzing with little jolts of electricity, and she had to take a deep breath to remember where she left off with her poor caster.

Chulainn growled and moaned with every stroke. The moment Robin began to move, slowly thrusting into her soft body, she fell into the same rhythm, running her hand up and down the caster’s length just so. It wasn’t enough to undo him, though, and so Ritsuka ventured a hand up behind his sack to lightly pull at the skin there.

“Ah!” Chulainn gasped, slapping a hand over his mouth too late to muffle the sound.

Ritsuka giggled, hyper aware of both men’s eyes on her. “Oh? What was that? Cu, you kept saying you’d hear me scream, and now you won’t even return the favor? How rude.”

She felt Robin’s pace falter as he chuckled and laid yet more kisses on her back. _Is he speeding up?_ the young Master pondered. _I swear he started off slower. Huh._

Chulainn tried to glare at the other two, but it looked far more pained than angry. Yet he kept his hand in place. Ritsuka would have to do more to encourage him. She leaned down, lips nearly brushing his weeping tip, and exhaled softly. The shiver that went up his body was instantaneous, but she didn’t go further. She held his gaze, on the verge of giving him more, waiting for him to move first. A moment passed where the only noise was the soft slap of flesh from Robin’s steady thrusts.

The caster let out a groan and shakily lowered his hand from his mouth. He reached towards Ritsuka’s head, and for a moment, she thought that he was going to grab her hair and force her onto his cock. But he paused with his fingers against her temple and went no further. Cautiously, she took his tip into her mouth and ran her tongue around the head.

Chulainn gasped again, although this time it was significantly higher pitched. His fingers tangled in her hair uncertainly. “M-Master…”

“Just relax,” Ritsuka said, fondling his balls in one hand while continuing to stroke with the other. “It’s my turn to make you come.”

“You haven’t forgotten about me, right?” Robin muttered against her shoulder. His thrusts were becoming more and more staccato, and she was sure she would be seeing stars again any moment as the tension built to its peak again.

With so many things happening all at once, all Ritsuka could say was, “Robin…” And then she took Chulainn into her mouth again, eager to see how he fell apart at his climax.

A few more thrusts, and Ritsuka went over the edge, moaning and sighing against the caster’s hips. Robin wasn’t too far behind, shivering against her body as he found his own release. Chulainn came last, spilling his seed over his chest as Ritsuka had to catch her breath. They stayed like that for a few precious moments, letting the last waves of pleasure roll over them before they pulled apart.

Ritsuka was just able to move to Chulainn’s side before the exhaustion she’d been pushing away came crashing back down. She wrapped her arms around the caster’s chest and slipped into a deep sleep the moment her head touched her pillow.

 

* * * * * * * * * *

 

"Did she climax and then fall asleep?”

“Looks like it.”

“Damn… I’m losing my touch.”

“She did look tired when we came back from the singularity.”

Chulainn eyed the green-clad archer as he picked his cloak back up off the floor. “Hm, you might be right about that,” the caster agreed. He idly stroked their master’s hair as he spoke. It wasn’t like he would be moving anytime soon. Chulainn wasn’t in that much of a rush to wake her up by moving out of her arms.

Plus, the contact was kind of nice.

Robin slunk back onto the bed with his cloak. He lay down against Ritsuka’s back and placed the cloak over the three of them like a blanket. Compared to some of the actual blankets the staff at Chaldea had, it was incredibly warm. Their master would probably appreciate the gesture, even if it did smell like damp wood and deer musk.

“I don’t think you ever got her to actually scream, did you?” Robin said after a while. His voice lacked the bitter antagonism it had when he first entered the room.

Chulainn huffed. He didn’t want to admit it, but she hadn’t. He really was losing his touch.

“You know,” the archer continued, “I’m pretty sure that she would have if we were working together.”

“Maybe…” Chulainn mumbled. He had an idea of where Robin was going, but he wasn’t sure how he felt about it. “First, she needs to wake up.”

“Yeah, needs to wake up,” Robin agreed, cuddling Ritsuka.

And they said nothing else for a while, because nothing else needed to be said.

**Author's Note:**

> Poor Diarmuid. He just wanted to talk about battle strategy.
> 
> As always, comments and critiques are greatly appreciated.


End file.
